Electric furnace.



PATENTED JULY 9, 1907.

E. A. GOLBY. ELECTRIC FURNACE.

APPLIOATION FILED NOV.23,1906.

4 SHEETS-SHEET 1.

gill! WlTNESSES: I

g mam PATENTED JULY 9, 1907.

E. A. COLBY.

ELECTRIC FURNACE.

APPLICATION FILED NOV.23,1906.

4 SHEETS-SEEET 2.

ATTORNEY I I 1 I I PATENTED JULY 9, 1907.

E. A. COLBY.

ELECTRIC FURNACE.

APPLICATION FILED NOV.23,1906.

4 SHEETS-SHEET 3.

PATENTED JULY 9, 1907.

13. A. COLBY. ELECTRIC FURNACE.

APPLICATION IILED NOV.23,1905.

4 SHEETS-SHEET 4.

III!!! F ll I hereinafter set forth.

' of asbestos board, in the space To all whom it struction of theinduction furnace by renderingthe UNITED STATES p grnn'r orruon.

EDWARD A. COLBY, OF NEWARK, NEW JERSEY, ASSIGNOR TO AMERICAN ELECTRICFURNACE COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC FURNACE.

' No. 859,641. Specification of Letters Patent.

Applicltiou fil d November 23,1905. Serial No. 288,630.

members 8 and 9 and receive between them the upper laminated framemembers 13 and 14. The plates 12 have edge recesses to receive the endpivot pins of earns 15 and 16. Said cams are provided with levers 17 byforcing down which as shown in Fig. 2, the outer ends of the uppermembers 13, 14 are pressed tightly against the upper ends of the sidemembers 8 and 9.

The inner ends of members 13 and 14 meet directly above the middle framemember or core 18 which extends through the space surrounded by thecrucible 1 and bears upon the lower frame member 6. In the upper end ofcore 18 are recesses to receive dowel pins 19 which enter correspondingrecesses on the under side of members 1.3, 14. In the lower ends aresimilar recesses and dowel pins 19 Bolted on opposite sides of the core18, are plates 20 which extend upwardly and receive between them theabutting ends of members 13, 14. In said plates are edge recessessimilar to'thosc in plates 12, which receive end pivot pins of a similarcam 21, provided with a hand lever 22, which can be brought down toforce the inner ends of members 13, 14 tightly against the upper end ofthe core 18.

It will be seen that by this construction the upper members of thelaminated frame of magnetic material may be clamp ed tightly down uponthe side and middle members so as to insure close metallic contact. Theupper members 13, 14, however, are easily detachable, since the cam pinsmay readily be taken out from the edge recesses in plates 12 and 20,thus allowing of the removal of the cams and the lifting out of saidmembers from between said plates. The object of making the upper framemember in practically two parts 13, 14 is to facilitate this removal.

From the horizontal section shown in F ig. 3, it will be seen that thelaminated core 18 has its laminations of such widths as to form verticalstepped recesses on its exterior. These recesses receive tubes 23 ofporcelain, fire clay or other insulating material which prevent contactof the core 18 and the inducing coil 24 which surrounds it.

The inducing coil 24 is preferably a tube of copper, and has its turnsof sufficient diameter to permit it to lie in close proximity to thesurrounding wall of the crucible. It rests upon a ring 25 of refractorymaterial supported by lower frame member 6 between which ring and thecrucible and core there are open spaces for air may concern:

Be it known that 1, EDWARD A. COLBY, a citizen of the United States,residing at Newark, in the county of Essex and State of New Jersey, haveinvented a certain new and useful Improvement in Electric Furnaces, ofwhich the following is a specification.

' The invention relates to an electric induction furnace of the type setforth in U. S. Lette'rsPatent No. 428,378 granted to me May 20, 1890.

The invention consists in the construction of the frame of magneticmaterial; also in a tubular inducing coil; also in the devices forholding the coil; also in the insulating blocks disposed between thecoil turns and their arrangement; also in the means for establishingliquid circulation and electric circuit in the coil; also in the variouscombinations more particularly The object of the invention is to improvethe conparts more eas'ly'assembled and detached, to improve the inducingcoil and its insulation and to provide for effective circulation ofrefrigerating liquid therein.

In the accompanying drawings-Figure 1 is a top view of my improvedinduction furnace. Fig. 2 is an elevation show'ng the crucible and itssupport in vertical section. the line a: .r of Fig. 4. 4 is a sideelevation of the coil, core and upper member of the frame. of the same.Fig. 6 shows the arrangement of the coil and separating blocks ofinsulating material. Fig. 7 is a transverse section of a preferred formof crucible showing the heat insulating covering thereof. Fig. 8 is atop view of the coil terminals showing the mode of connecting them tothe electric mains and also to the source of water supply. Fig. 9 showsa side view of the same, the coil tube at its junction with the watersupply conduitbeing in section.

Similar numbers of reference indicate like parts.

1 is the crucible in annular form, having the charge receiving chamber2. Said crucible rests upon the base plate 3 and is provided with ajacket 4, preferably between which and the crucible heat insulatingmaterial, such as magnesia may be placed as shown at 5, Fig. 7. The baseplate 3 which may be of soap-stone is secured upon the lower member 6 ofa frame of laminated magnetic ma-' terial. To the ends of said lowermember are bolted circulation.

the vertical members 8 and 9, to which are secured Interposed betweenthe turns of coil 24 are separat flanged plates 10, to the outer facesof the flanges of ing blocks 27, Fig; 6, of refractory insulatingmaterial. which are bolted the circular plates 11, which carry Eachblock has a semi-circular recess in its opposite can be tilted whendesired.

. vSaid trunnions are received in any suit- (not shown), so that theentire furnace trunnions 7. able housing The if: ngcd plates 12 extendabove the upper ends of blocks are held together slots through whichpasses in it from the coil 24 Whch coil with them held down upon thering by means of the plates 28 on opposite sides of core 18. Said plateshave flanges 29 on their lower extremities covered beneath withinsulating layers 30, which insulating layers rest upon the coil 24. Theplates ZSh-ave vertical the bolt 31, which also serves to secure theplates 20 to core 18. Bolt 31 is threaded and provided with a nut, sothat it can be loosened to allow plates 28 to be adjustedvertically.

The coil 24 is made tubular in order to admit of Waframe of magneticmaterial surrounding said cru 'ibic h.-i\'ing a detachable upper memberand a detachable Illlt: 1 member extending through said crucible.

4. in an electric furnace of the type settorlh. having a crucible and aninducingcoil. a rectangular frame of magnetic material surrounding saidcrucible and coil, and means for detachably securing the upper member ofsaid frame to the side members thereof.

In an electric furnace of the type set forth, having an annular crucibleand an inducing coil, a rectangular frame of magnetic materialsurrounding said crucible and coil and having, a middle member extendingthrough said coi and means for detachably securing said upper member (oter circulation through it for cooling purposes. The the Side and middlemembers of i mum, electrical iilld WliOl COIIIIGCUO IS 0f he C0 l best(5. In an electric furnace of the type set forth, having an SlIOWIl inFigs. 8 and 9. annular crucible and an inducing coil. a rectangulariraiuc of magnetic material surrounding said crucible and coi andhavinga middle member extending through said coil, and an upper memberin two parts with their ends tlllli 'w ting above said middle member,means for detachably curing the outer ends of said upper member to themembers of said frame and the inner abutting ends to middle member.

7. In an electric furnace of the type set forth, lmvlzu: an annularcrucible and an inducing coil, a rectangular frame of magnetic materialsurrounding said crucible and 32 is a casting having a downwardly turnedduct 33, and provided at one end of said duct with a threaded projectionto receive the coupling nut 34 for the attachment thereto of the flangedthimble 35 on the end of water conveying hose-36. To the other end ofthe duct the coil tube 24 is secured by brazing, or in any otherconvenient way. On said casting is also formed the flat partly circularlug 37 to one face of which is secured by means of the bolt 38 acircular plate 39 integral with the tube 40, in which tube theelectrical conductor 41 leading from the source of current is insertedand fastened by any suitable means. A second casting 42, similarlyconstructed, receives the return hose 43 and return conductor 44. Bothcastings have side member in contac: with the extremities of the sidemembers of said frame.

frame, alplate 47 of insulating material being interposed. 'For thepurpose of conveniently connecting a measuring instrument (not shown)for determining, potential differences at the coil terminals, conductingconnected to the castings by the fastening bolts 40. Liquid, therefore,circulates from hose 35 through casting 32 to coil24, to casting 42 andreturn hose 43, or vice versa.

an annular crucible a rectangular frame of magnetic material surroundingsaid crucible hava vertically movable upper member and a middle memborextending through said crucible and means for press ing and holding saidupper member in contact with the extremities of said middle member andthe side members of said frame.

10. In an electric furnace of the type set forth, having a crucible anda removable inducing coil, :1 support, and menus acting on one face ofsaid coil for holding said coil against said support.

11. In an electric furnace of the type set forth, having a crucible anda removable inducing coll, a support below said coil and means forholding said coil down on said support.

12. In an electric furnace of the type set forth, a crucible and aremovable inducing, coil, a support said coil and adjustable means forholding said coll upon said support.

12. In an electric furnace of the type herein set forth, having anannular crucible and an inducing coil, :1 rectangular frame surroundingand supporting said crucible and coil and having a middle memberextending through said coil and means on said middle member for holdingsaid coil down upon the lower member of said frame.

14. In an electric furnace of the type set forth, an inducing coilhaving a plurality of turns and separated bodies of refractoryinsulating material interposed between said turns.

15. In an electric In order more perfectly to prevent heat radiationfrom the crucible I may form on the under side thereof and below themelting chamber an annular recess 49, and pack it with heat insulatingmaterial as shown in Fig. 7.

For the purpose of conveniently disconnecting the coil 24 in order toremove it from the apparatus, I provide detachable couplings 50 in thetube.

In operation the charge to be heated is placed in the crucible chamber2, and is melted by currents induced is connected with a source ofalternating current. The charge when melted may be poured into a mold orot er receptacle by suitably tilting the furnace, and during the meltingoperation the furnace may be rocked on its trunnions, if desired.

I claim:

1. In an electric furnace of the type set forth, having an r annularcrucible and an inducing coil, a frame of magnetic material surroundingsaid crucible and coil and having, a detachable member extending throughsaid crucible.

2. In an electric having: below down furnace of the type set forth, anin ducing coil having a plurality of turns and separated bodies ofrefractory insulating material having recesses to receive the coilconductor and disposed between said In combination with the crucible ofan electric induction furnace, an inducing coil having a plurality ofturns separated by an air material surrounding and supporting said.crucible and coil and having a detachable middle member extendingthrough said crucible.

3 In an electric furnace of the type set forth, having an annularcrucible and an inducing coil, a rectangularsaid space between crucibleand core: the said coil being construcied and arranged so that thereshall be free air circulation through, outside of and between the turnsof said coil.

18. The combination of an electric furnace of a frame of magneticmaterial, an annular crucible Supported therein, a core in the circularspace surrounded by said crucible, an inducing coil disposed in saidspace between crucible and core and a ring of insulating materialsupporting said coil and supported by the lower member of said frame. I

19. In an electric furnace of the type set forth, an inducing coilhaving a plurality of turns and separted bodies of insulating materialhaving recesses to receive the coil conductor, disposed between saidturns and superposed in contact to form a vertical column.

.20. In an electric furnace of the type set forth, a support, aninducing coil therein having a plurality of turns, bodies of insulatingmaterial having recesses to receive the coil conductor disposed betweensaid turns and super posed in contact to form a vertical column andmeans acting downwardly in said coil to hold said bodies in contact.

21. In combination with the crucible of an electric in duction furnacewherein the charge forms a secondary circuit, a primary coil inproximity to said crucible, and means for preventing variations in theelectrical resistance of said coil due tofheat-radiated from saidcrucible.

22. The combination with the crucible of an electric in duction furnacewherein the charge forms a secondary circuit, a tubular primary coil inproximity to said crucible and means for establishing a current ofcooling medium through said coil.

23. In combination with the crucible of an electric induction furnacewherein the charge forms a secondary circuit, a tubular primary coildisposed in the circular space surrounded by said crucible and means forestablishing liquid circulation in said coil.

2-1. In combination with the crucible of an electric induction furnacewherein the charge forms a secondary circuit, a tubular primary coildisposed in the circular space surrounded by said crucible, a core ofmagnetic material within said coil, and means for establishing liquidcirculation in said coil.

25. In an electric furnace of the type set forth, an in 'ducing coil, asupport therefor and means for detachably clamping said coil to saidsupport.

26. In an electric furnace of the type set forth, a crucible, aninducing coil, :1 support common to both and means for detachablyclamping said coil to said support.

27. In an electric furnace of the type set forth, a

.crucible, an inducing coil, 11 core of magnetic material,

a support for said parts and means for detachably clamp-' ing said coiland said core to said support.

28. In an electric furnace of the type set forth, a crucible andinducing coil, :1 core of magnetic material, a support for said partsand means for detachably clamping said core to said support.

29. In an electric furnace of the type set forth, a crucible, aninducing coil surrounded thereby, a core of magnetic material withinsaid coil and means for removably holding said core in said coil.

30. In an electric furnace of the type set forth, a tubular inducingcoil, a support therefor, means of supply of refrigerating liquid andelectric current to said coil and means for removably disconnecting saidcoil from said support. and from said liquid and current supply.

131. In an electric furnace of the type set forth, an inducing coil, acore of magnetic material therein having longitudinal recesses andbodies of insulating material disposed in said recesses and between saidcoil and said core.

32. In an electric furnace of the type set forth, an inducing coil, acore of magnetic material therein having longitudinal recesses and tubesof insulating material disposed in said recesses and between said coiland said,

core.

33. In an electric furnace of the type set forth, an inducing coil, acore of laminated magnetic material therein and having its laminationsof difierent widths to form symetricnlly disposed longitudinal recessesand tubes of insulating material disposed in said recesses and betweensaid coil and said core.

3-1. The combination in an electric induction furnace of a crucible, aterminal of conducting material having a duct, means for connecting aliquid conduit to said duct, means for electrically connecting anelectric conductor to said terminal and means for electricallyconnecting said tubular coil to said terminal and said duct.

35. The combination with a fixed member of an electric induction furnaceof a tubular bracket of conducting material, a contact plate integraltherewith, an electric conductor, means for connecting said conductor tosaid contact plate, two conduits, means for connecting a conduit to eachend of said tube in said bracket, an nducing coil, and means forconnecting one of said conduits to said coil.

36. The combination of a tubular bracket of conducting material, acontact plate therein, pipe connections at each end of said brackettube, a second contact plate, means for detachably connecting saidcontact plates and means for securing an electrical conductor to saidsecond contact plate.

In testimony whereof I have aflixed my signature in presence of twowitnesses.

/ EDWARD A. COLBY.

